This invention relates to lubrication systems, and more specifically to low pressure lubrication systems for bearings in external gear pumps and motors.
It is common to make use of the fluid being pumped in a gear pump to lubricate the shafts and bearings in the pump. This is accomplished by various lubrication systems which usually include one or more grooves along each bearing, the groove or grooves being connected to fluid at different pressures, for example, inlet and outlet pressure or inlet pressure and pressure at the area where the gear teeth break mesh, in order to provide a fluid flow through the particular system. It is, of course, desirable to have a continuous flow of fluid through any such lubrication system because, among other things, it serves to cool the bearings.
I have learned that not all lubrication systems for gear pumps which connect the bearings to areas of different fluid pressures reliably provide a fluid flow past the bearings. In order to provide a reliable and significant fluid flow past the bearings I provide a lubrication system in which the shafts and bearings function as viscous shear pumps so that fluid is pumped past the bearings. This also has the advantage of providing a fluid flow while permitting the bearings to be connected to a single fluid pressure area, preferably the inlet or low pressure port.